Snap switch



O United States Patent 13,549,838

[ 72] inventor Carl A.H.M. Waskowsky [56] References Cited Oberglatt,Zurich, Switzerland UNITED STATES PATENTS [211 P 7511128 3 3,201,5418/1965 Richert 335/203 PM 81 1968 3,352,983 11/1967 Cools 200/83 [451 3360 197 12/1967 Stringham 335/1x Patinvest Patent und Investment A.G.[731 Asslgnee Chm Switwland 3,434,081 3/1969 Foster 335/203 3,4 2 1 l9 9l 00 32 Priority Sept. 15,1967 50 6 Eg1 2 /83 [33] Germany PrimaryExammer-Robert K. Schaefer [3] 1 No. 1,665,383 Assistant Examiner-J. R.Scott Attorneyl(arl F. Ross [54] SNAP SWITCH 4 Claims 6 Drawmg ABSTRACT:A combination of several switch units side [52] US. Cl 200/83, by sidein one housing includes at least one 200/168, 335/ 1 317/99pressure-controlled switch unit actuated by [5] 1 Int. Cl. H0lh 35/40, adiaphragm and at least one electrically H02b 1/08 controlled switch unitactuated by an [50] Field of Search 200/83, electromagnet forcontrolling the 83.9, 153, 168A; 1535/], 185, 192, 203, 15, 28, 29,operation ofdifferent elements ofone 49, 53, 162, 186, 188, 194; 317/99,112 machine, for example, a washing machine.

J19 M 3 I9 45 7 JJ J1 L. if f INVENTOR ,CARL A n wwkxsxowsm PATENTEDUEC22 I970 ATTORNEY I PATENTEB UEC22 I970 sum ear 4 Z I 52\ /5. f

' ATTORNEY SHEET am 4 PATENTEU DEB22 I970 SARL d H h NAJKUL'JLLAYINVENTOR ATTORNEY SNAP SWITCH The present invention relates to amultipole snap switch which is especially adapted for being employed ina laundering or dish-washing machine or the like whose individual switchunits are equipped with contact springs for making and breaking one ormore circuits.

The switch systems of such multipole switches are generally controlledby means of a diaphragm responsive to a pressure which depends upon thelevel of the liquid contained in the respective machine and acts uponspring-loaded control levers operating the contact springs. Suchpressure-controlled switches are frequently employed for carrying out aswitching operation when a predetermined pressure is reached. A switchof this type may also be controlled by a temperature gauge whichconverts the temperatures acting thereon into pressures. Owing to theirdesign and functions, the switches con trolled by suchtemperature-pressure converters do, however,

not operate at very specific temperatures and pressures but.

within relatively large temperature and pressure ranges. For this reasonelectronic temperature sensors known as thermistors are often preferredwhich not only operate more accurately but may also be easily separatedfrom the actual switches since they are connected thereto merelyelectrically, in contradistinction to the temperature-pressureconverters mentioned above.

It is an object of the present invention to provide a multipolarsnap-action switch of the type mentioned above which is responsive tochanges in pressure and may in addition be used for carrying outswitching operations in response to conditions or parameters independentof pressures.

According to the invention, this object is attained by designing theswitch so that the operations of at least one of the switch unitsthereof may be controlled by an electrically controlled switch elensent,while the operations of at least one further switch unit may becontrolled by a switch element which is responsive to a pressuredetermined, for example, by the level of a liquid in a container ormachine. This combination of two different switch systems has theparticular advantage that the difierent switching operations can beperformed by a single multipolar switch which is of reliableconstruction and also operates accurately at all times even though ithas to comply with different requirements.

According to one preferred embodiment of the invention, the controlelement of the electric switch unit of the multipolar switch is in theform of an electromagnet with a pivotable armature whose free end isconnected to a contact spring so as to pivot the same into or out ofengagement with a fixed contact.

This electrically controlled switch unit, which may be located betweentwo pressure-controlled switch units and could be exchanged, if desired,for another pressure-controlled switch unit, may also be connected toand actuated by an electronic control system which is responsive, forexample, to a temperature value which is determined by an electronicsensor or thermistor.

These and additional features and advantages of the present inventionwill become further apparent from the following detailed descriptionthereof which is to be read with reference to the accompanying drawingin which:

H6. 1 shows a cross section of the switch taken along the line 1-1ofFlG. 2;

FIG. 2 shows an axial section taken along the line 2-2 of FIG. 1;

FIG. 3 shows an enlarged view of a part of the switch illustrated inFIG. 2;

FIG. 4 shows an axial section taken along the line 4-4 of FIG. 1;

FIG. 5 shows a diagram of the electric circuitry the switch; and

FIG. 6 shows a diagrammatic illustration ofthe electrically controlledswitch unit together with an electronic controlsystern therefor.

As illustrated in the drawing, the multipole switching device accordingto the invention comprises a housing 1 in which, as shown particularlyin FIG. 1, three switch units are mounted side-by-side, namely a centralswitch unit 2 which is electrically controlled and two outer switchunits 3 and 4 each of which is pressure-controlled.

The electric switch system 2 as illustrated in detail in FIGS. 2 and 3comprises a fixed contact 6 connected to a terminal 5, and a contactspring 8 which is connected to another terminal 7 and carries on itsfree end a contact 9 which, under the biasing stress of contact spring8, normally engages the fixed contact 6. Above this contact spring 8,the housing 3 carries an electromagnet 10 connected by conductors 11 and12 to two terminals 13 and 14 which are electrically insulated from eachother and through which the control current is supplied to theelectromagnet 10. This electromagnet 10. is provided with an armature 15which is pivotably mounted on the free end of a bracket 16 adjacent tothe electromagnet and has a contact projection 18 on its side facing thecore 17 of the electromagnet. On its opposite, lower side, the pivotablearmature 15 carries a pin 19 which projects through a longitudinal slot20 in the contact spring 8 and terminates in a head 21 of a width largerthan that of the slot 20.

The mode of operation of this electrically controlled switch unit 2 isas follows: When the electromagnet 10 is energized by a control currentwhich is supplied thereto from the terminals 13 and 14 through theconductors l1 and 12, the armature i5 is attracted to its closedposition as shown in FIG. 2 in which it has lifted the contact spring 8to its'open position. If the control current is then interrupted and theelectromagnet is deenergized, contact spring 8 is swung back by itsinherent stress in the direction of the arrow 22 so that its contact 9engages the fixed contact 6 as shown in FIG. 3 and thereby interconnectsthe two terminals 5 and 7 to close the circuit of the switch unit 2.This return swing of contact spring 8 also draws the armature l5 to itsopen position as shown in FIG. 3. Switch unit 2 then remains in itsclosed position until another current impulse is supplied to theelectromagnet 10 whereupon the attraction of armature 15 moves thecontact spring 8 against its biasing stress to its open position.

Instead of being inherently biased, contact spring 8 may also be actedupon by a pressure or draw spring. It is also possible to mount thefixed contact at the other side of the movable contact 9 in the mannerindicated in FIGS. 1 and 2 in dotted lines, in which case the circuit ofthe electric switch unit 2 will always be closed when a control currenttraverses the electromagnet l0 and the armature 15 is in its attractedposition. As soon as the .control current is then interrupted, contactspring 8 is returned by its own bias or by the action of a separatespring to its open position.

Which of the two different arrangements of the fixed contact 6 is to beemployed depends upon the particular use of the switch. If the fixedcontact 6 is located underneath the contact spring 8, theelectromagnetic attraction of contact spring 8 will cause the contactsto be quickly separated so that any are will also be quicklyextinguished. If, however, the control current acting upon theelectromagnet 10 is interrupted, the switch unit 2 (which may control,for example, the circuit of an electric heating apparatus) will beclosed so that its load will also operate continuously. lf, however, thefixed contact 6 is located above the contact spring 8, an interruptionof the control current of the electromagnet 10 will also cause theswitch unit 2 to be switched off. This advantage will, however, beoffset by the disadvantage that the contact spring 8 will then returnrather slowly to its open position which willcause stronger arcing ofthe contacts.

FIG. 4 illustrates the assembly 5 representative of the two pressurecontrolled switch units 3 and 4 which are located at both sides of theelectrically controlled switch unit 2 as previously described. Switchunit 3 is controlled by a diaphragm 23 responsive to the pressure of aliquid or gas which enters the lower part of the housing 1 underneathdiaphragm 23 through an inlet 24. This diaphragm 23 acts by a tappet 26,mounted onja diaphragm plate upon a control lever 27 which is pifvotableabout one end and acted upon by an adjusting spring 28 whose-other endengages a setscrew 30 which may be adjusted to different levels in asocket 29 in the switch housing 1. 4 The control lever 27 is operativelyassociated with a contact spring 31, fixedly clamped at one end, whichis provided with an aperturethrough which an extension 37 of the controllever may swing and with a contact 32 on its free end located betweentwo fixed switch contacts 33 and 34 the latter of which is adjustable todifferent levels by a setscrew 44 in a socket 43. Between this contactspring 31 and the control lever 27 a snap spring 35 is provided whichengages with one lend'the edge of the aperture in contact spring 31 andwith its Qt er end the projecting end 36 of the extension 37 of controlleveftfi27.

Elements of unit 4 visible in FIG. 7 bear the same designations, withthe addition of a'prime mark, as corresponding elernjnts of unit 3.

when the switch unit 3 or 4 is in the position as shown in FIG; 4,diaphragm 23 is in its raised operative position in which the controllever 27 is pivoted upwardly against the action, of the adjusting spring28 and the contact 32 of contact spring 31 engages the fixed contact 33so that the terminals 38 arid. 39 are electrically interconnected. Whendiaphragm 23 returns, however, to its inactive position as shown indot-dash liriesfin FIG. 4, and settles on the supporting rim 41 on theinner side of the cover of housing 1, control lever 27 carriesoutapivoting movement in the bottom portion or direction of thiefarrow42 so that toggle spring 35 snaps over to the other s ide with theresultthat contact spring 31 swings in the opp'o'site direction and itscontact 32 engages the other contact 34. Terminal 38, fixed end ofspring 31, is then in circuit with another terminal 45.

The electric circuits of the switching system according to the' invention are illustrated diagrammatically in FIG. 5, in which theterminalsand contacts are designated by the same reference numerals asin the preceding FIGS. Here again, the reference numerals for the switchunit 4 differ from those used for the switch unit 3 by the addition of aprime mark.

FIG. 6, finally, shows a diagrammatic illustration of an electroniccontrol of the electrical switch unit 2 which, in turn, controls thesupply of current to an electric heating device 47 connected to thecurrent source 46. This electronic circuit comprises an amplifier 48 oneside of which is connected to a temperature sensor or thermistor 49,such as a temperatureresponsive resistance, while its other side isconnected to a power-supply unit 50 energized by electric mains 46.

From FIGS. 1-3 it will be noted that the diaphragm 23 with itsreinforcing plate 25 extends across the entire dished housing bottom 40,underneath switch units 2, 3 and 4, even thoughonly the latter two units(flanking the unit 2) are actuated by this diaphragm through theintermediary of their levers 27 and 27' upon admission of pressure fluidinto the chamber 55 beneath it. It will also be seen that the oppositehousing portion, overlying the diaphragm, is formed with asuperstructure 51, 52 which defines a recess bounded by edges 53, 54 toaccommodate parts of the units2, 3 and 4, thereby keeping the elementsof unit 2 clear ofdiaphragm 23 in any position of the latter whileaffording enough room for the operation of the diaphragm-controlledlevers of units 3 and 4.

From the above description and the drawing it is evident that thisparticular switch is in effect a two-level control switch, for example,of a washing machine, which by means of its electrically controlledswitch unit is additionally able .to control the operation of anelectric heating unit of the machine. By thus combining two differentswitch systems into one structural unit it. is possible to omit aseparate additional switch as well as separate contactors.

Although my invention has been illustrated and described with referenceto the preferred embodiment thereof, 1 wish to have it understood thatit is in no way limited to the details of such embodiment but is capableof numerous modifications within the scope of the appended claims.

lclaim:

1. A switching'device comprising ahousing with a dished bottom portion,a diaphragm spanning said bottom portion within said housing and forminga pressure chamber with said bottom portion, fluid-supply means openinginto said chamber for raising and lowering said diaphragm, said housingalso having a recessed top portion overlying said diaphragm, and aplurality of switch units above said diaphragm partly accommodated insaid recessed top portion, said switch units including a first unitwithfluid-controlled actuating means responsive to movement of said"diaphragm and a second unit with electrically controlled actuatingmeans positioned sufficiently remote from saiddiaphragm to be unaffectedby such movement.

2. A switching. device as defined in claim 1 wherein said switch unitsinclude a third unit substantially identical with said first unit, saidsecond unit'being flanked by said first and third units and lying at thecenter of said housing.

3. A switching device as defined in claim 1 wherein said second unitcomprises electromagnetic means substantially completely withdrawn intosaid recessed top portion, contact means between said electromagneticmeans and said diaphragm, and armature means for said electromagneticmeans coupled with said contact means.

4. A switching deviceas defined in claim 1 wherein said first unitcomprises lever means bearing upon said diaphragm, a toggle mechanismlinked with said lever means, and contacts alternately openable andclosable by said toggle mechanism.

